The purpose of this thesis was to explore whether there is a direct route to action from
vision, in which the selection of action is constrained by perceptual information from
objects as well as by more abstract semantic knowledge. A connectionist model, NAM
(Naming and Action Model) was developed, incorporating a direct perceptual route to
action along with an indirect semantic route. This was used to simulate data from
normal observers and neuropsychological patients. In addition to this, new empirical
data were collected to provide a better understanding of the types of visual information
used in action selection. One set of new experiments provided evidence that two
variables, object viewpoint and semantic priming, differentially affect action and
semantic decisions to objects. A further set of experiments showed that action
verification tasks (e. g., is this drinking? ) could be facilitated by congruent information
about handgrip - provided either by a static or a moving hand. This indicates that a
direct route to action is sensitive to linked information about handgrip and movement.
Finally, the direct route to action was examined through a case study of an optic aphasic
patient. This patient showed spared naming of verbs relative to objects, but the opposite
pattern of sparing occurred in reading. This double dissociation, within a patient,
suggests that verb retrieval for objects can operate non-semantically. These
computational, psychological and neuropsychological data provide evidence for a direct
route to action.